Secret fleet: airborne signals intelligence

EATURES
Date Posted: 15-Jul-2008

Jane's Defence Weekly

Secret fleet: airborne signals intelligence

Martin Streetly Jane's Electronic Mission Aircraft Editor - London

Key Points
Operational needs have pushed forwards the development of SIGINT platforms that can support action by troops on the ground

Increasingly complex systems have become smaller and more easily upgraded, while offering richer, more timely data


Armed forces deploy various air platforms on crucial SIGINT missions around the world. Martin Streetly assesses their capabilities

Like many of today's military technologies, airborne signals intelligence (SIGINT) collection has undergone profound changes since Operation 'Desert Storm'.

Prior to the 1990-91 Gulf War, airborne SIGINT was primarily a strategic activity, with a heavy emphasis on 'bean counting' air-defence radars (electronic intelligence, ELINT), monitoring military and political communications networks (communications intelligence, COMINT), establishing the technical parameters of strategic missiles (via the interception of associated telemetry traffic: telemetry intelligence, TELINT) and military emitters such as radars (technical intelligence, TECHINT).

Operation 'Desert Storm' marked the first attempt since the Vietnam War to employ SIGINT collected by air vehicles (AVs) ina tactical context, where acquired data could be used in real or near-real time to inform warfighters of threats and enemy intentions during operations.

Subsequent operations in the Balkans and particularly during the United States' 'global war on terror' have driven this process to the point where SIGINT platforms can now be used to detect, track, identify and monitor the fleeting, telephone-based/short-range radio communications employed by insurgents and pass the derived intelligence to warfighters in executable engagement times. Equally, ELINT and COMINT capabilities have become a standard component in multisensor platforms of the types used for maritime, economic exclusion zone and homeland defence surveillance applications.

In terms of technology, the basic laws of physics have not changed and today's SIGINT hardware functions in much the same way as its forebears.

What has changed is the ability to miniaturise; to integrate subsystems into open architectures that are much more easily upgraded (either as software fits or as hardware 'plug and play' drop-ins); to make use of commercially derived software and hardware in an environment that has traditionally been bespoke; to provide communications links (including machine-to-machine) that can provide real-time data hand-off for 'shooters'; and to process data in a way that is a quantum leap forward in terms of what information can be extracted from a particular intercept.

Such capabilities represent the high end of the genre and it is with these dedicated SIGINT platforms, rather than multisensor AVs, that this survey concerns itself. Jane's has identified 20 countries around the world that operate dedicated airborne SIGINT platforms.

Surveillance platforms
The first thing to be said about Australia's 'Peace Mate' programme is that its existence has never been officially confirmed and no photographs of either the C-130 or P-3 aircraft supposedly involved have ever surfaced in the public domain.

That said, Jane's analysts believe the Royal Australian Air Force does operate single examples of 'Peace Mate'-configured C-130 and P-3 SIGINT aircraft, with the latter understood to have been outfitted by US contractor Raytheon (subsequently L-3 Communications Integrated Systems [L-3/IS]) during 1995-97. They are thought to be able to undertake COMINT collection within the 3 MHz to 3 GHz frequency range, being equipped with a satellite communications capability.

The 'Peace Mate' C-130 is reported as having been modified by Australian contractor Tenix, as making use of a predominantly US-sourced mission suite and (like its P-3 counterpart) as being equipped with a satellite communications capability.

A little more certain is Chile's continued use of at least one　 of three Hawker Beechcraft 99A utility transports that have been locally modified for ELINT work under the 'Petrel Beta' designation. The capability centres on the30 MHz to 18 GHz band Desarrollo de Tecnologias y Sistemas (DTS) Itata ELINT system that incorporates analysis and direction-finding workstations. According to Jane's sources, Petrel Beta entered service in 1970, with three examples being reported as being operational during 2006.

Maintaining the enigmatic theme, China's airborne SIGINT capability appears to be vested in one　 or more variants of the Shaanxi Y-8 transport aircraft. As such, the capability appears to be part of the High and New (HN) programme, with subprojects 'HN 2' and 'HN 4' being suggested as SIGINT platforms. Alongside these, a model of a Y-8 equipped with the CEIEC KZ800 ELINT suite was displayed in April at the Defence Services Asia (DSA) 2008 trade show.

Covering at least the 1-18 GHz frequency band, the KZ800 system is understood to comprise multi-operator equipment that is designed to detect, analyse (parameter measurement), identify and locate land-based and shipborne radars that are associated with air-defence networks and gun/artillery/missile fire control systems.

Of the two HN configurations, Jane's sources identify HN 2 as being the Y-8DZ that was first spotted during mid-2004 and is said to be in service with the People's Liberation Army (PLA) Navy's 1st Independent Air Regiment. HN 4 has been associated with both the Y-8T and YG-8 designations and is reported as being in service with the PLA Air Force. Of the two, HN 4 makes the most convincing SIGINT platform, particularly as it shares several external features and antenna arrays with the previously noted DSA 2008 display model.

Elsewhere within the Chinese military, the air force is known to have been operating at least one　 Tu-154 airliner that appears to have been modified for SIGINT. This aircraft was first identified during the mid-1990s.

Moving to the Middle East, the Egyptian Air Force (EAF) has acquired at least two (and possibly four) Hawker Beechcraft 1900C-1 aircraft, together with two EC-130H transport aircraft for use as SIGINT collectors.

The 1900C-1s (possibly designated as the 1900C-1E variant) are understood to be equipped with a variant of the ESL/TRW (subsequently Northrop Grumman Mission Systems) ES5000 SIGINT suite that operates in four specific sub-bands (3-30 MHz, 30-300 MHz, 230-1,000 MHz and 300-3,000 MHz) within the 3-3,000 MHz frequency band. Other onb　oard equipment includes an air-to-ground datalink and, while not confirmed, the EAF's electric 1900C-1s have been associated with its No 81 Squadron.

Egypt's EC-130Hs are thought to be COMINT platforms that were outfitted by the then E-Systems (subsequently L-3/IS) and delivered circa 1978. In July 2003 the US Defence Security Co-operation Agency flagged up a potential USD60 million sale of two roll-on/roll-off ELINT systems for installation aboard two "existing" Egyptian C-130H aircraft. To date, the consummation of this deal remains uncertain.

Enigmatic mission
Meanwhile, the French Air Force's Airborne Electronic Squadron 1/54 operates a pair of C-160G Gabriel SIGINT aircraft that were first fielded in 1989. Configured for both COMINT and ELINT, the Gabriel provides accommodation for nine systems operators and has a mission suite that was originally built around Thales-sourced COMINT receivers and analysis gear, together with the same company's 0.5-40 GHz Analyseur de Signaux Tactiques (ASTAC) ELINT system. While not confirmed, Jane's believes these aircraft have been progressively upgraded during their service lives.

The German Navy's Naval Air Wing 3 operates a pair of Br-1150 Peace Peek SIGINT aircraft. Again equipped for the role by the ubiquitous E-Systems, the Peace Peek aircraft have been the subject of at least one　 major mission-suite upgrade and are scheduled to be replaced by the Euro Hawk unmanned aerial vehicle (UAV).

Based on the RQ-4 Block 20 airframe, the Euro Hawk SIGINT platform will be equipped with an EADS-developed COMINT/ELINT payload that covers the 30 kHz to approximately 30 GHz frequency band. As currently scheduled, the first Euro Hawk platform will be delivered in 2010 and, if successful, will be followed by four additional AVs during 2011-14.

The Israel Air Force's No 122 Squadron employs three Gulfstream V Shavit (Comet) SIGINT aircraft that are equipped with the Elta EL/I-3001 airborne integrated SIGINT system. The baseline EL/I-3001 offers both COMINT (20-1,200 MHz band) and ELINT (0.5-18 GHz band) capabilities. Operated by a 12-strong mission crew, the Shavit architecture incorporates both satellite communications and a datalink and is believed to have been used operationally for the first time in August 2006.

Israeli industry is also the source of the EL/K-7071 COMINT and EL/L-8385 ELINT payloads and the EL/L-8300 SIGINT suite that are believed to have been installed aboard the Indian Navy's four Israel Aerospace Industries Heron UAVs and Israeli C-130H SIGINT platforms respectively.

The Heron UAVs are assigned to India's Navy Air Squadron 342 and, while photographic evidence shows installation of the antenna arrays associated with the cited SIGINT payloads aboard such AVs, the payloads themselves may not be fitted. Use of an EL/L-8300 configuration aboard Israel's supposed pair of SIGINT C-130Hs is suggested by a 2001 Elta brief that noted installation of four such systems aboard Hercules transport aircraft.

Elsewhere within the Indian intelligence community, the Aviation Research Centre (ARC) includes a Boeing 707-337C SIGINT platform in its inventory of fixed- and rotary-wing aircraft. Characterised by 'cheek' antenna fairings, the ARC's B-707, which has been based at Indira Gandhi/Palam International Airport near Delhi, has been variously reported as being equipped with either a US or an Israeli mission suite. Jane's analysis leans towards the former because E-Systems documentation and the CIA's involvement in the establishment of the ARC during the 1960s supports this view.

India's known airborne SIGINT capability is rounded out by the 'information warfare' Do 228-201 aircraft operated by Naval Air Squadron 310. Such aircraft are equipped with a multiport antenna array at each wingtip and have been variously reported as being equipped with the 0.5-18 GHz Elisra AES-210/E Emerald electronic support (ES)/ELINT system or Bharat's up to 18 GHz Airborne ES System (AESS).

The Italian Air Force's 14th Wing includes a single G222VS SIGINT aircraft within its inventory. The G222VS is understood to be equipped with both Italian and US-sourced mission equipment and as providing accommodation for 10 system operators. Entering service in 1981, the G222VS is deemed to be in need of replacement, with a roll-on/roll-off capability installed aboard a C-130 being a mooted alternative. However, no replacement has been funded to date.

Naval patrol
Turning to East Asia, both Japan and South Korea operate SIGINT aircraft, with the former's capability being primarily vested in the Japan Maritime Self-Defence Force's (JMSDF's) EP-3 platform.

Based on a Kawasaki-built P-3C maritime patrol aircraft airframe, the EP-3 was first flown in October 1990. It is equipped with a mission suite that covers the 30 MHz to20 GHz frequency band and has been jointly developed by Japanese contractors NEC ('low'-band segment) and Mitsubishi ('high'-band segment). The designations NH/LR-107 and NH/LR-108 have been authoritatively associated with the two subsystems, although the specific nomenclature to band coverage relationship remains unclear. Elsewhere, the type is reported as being flown and operated by a crew of 23 and as having both TELINT and SIGINT capabilities. The JMSDF has acquired five EP-3 aircraft that are assigned to its 81st Squadron.

The Republic of Korea Air Force (RoKAF) operates a quartet of Hawker 800SIG SIGINT-configured business aircraft (also known as the RC-800 or the 'Paekdu/Peace Pioneer' platform) as part of the surveillance capability that is used to monitor the activities of its northern neighbour on the Korean peninsula. Like many other platforms, the Hawker 800SIG is fitted with a COMINT/ELINT system that was developed by E-Systems and which is quoted as having an upper frequency limit of 40 GHz. While not confirmed, the RC-800s may be assigned to the RoKAF's 39th Tactical Reconnaissance Wing.

Elsewhere in the region, both Singapore and Taiwan are understood to operate single examples of SIGINT-configured C-130s. The Singaporean platform is thought to have been outfitted by Israeli industry and is said to cover the 3 MHz to 3 GHz COMINT band.

Taiwan's C-130HE has been developed by a consortium of Lockheed Martin and the country's Chung Shan Institute of Science and Technology and is reported as having been assigned to the Taiwanese Air Force'sNo 6 Squadron. The Royal Thai Air Force's No 402 Squadron operates three Arava 201 transports that have been outfitted with an Israeli SIGINT system.

Returning to a European orbit, Poland, Spain, Sweden and the UK have all fielded airborne SIGINT platforms. The Polish Air Force operates at least one　 (possibly three) W-3RR Procjon-3 SIGINT helicopters equipped with a Polish-developed mission suite that incorporates two operator consoles and covers the 20-18,000 MHz frequency band.

Within the Spanish Air Force, the 47th Mixed Group operates a single Boeing 707-351C SCAPA aircraft that is configured for both electro-optical (EO) imaging and SIGINT collection. As originally developed, the SCAPA platform made use of hardware from the Elta EL/L-8300 COMINT/ELINT suite married to core software created by local manufacturer Indra.

The Swedish Air Force's 17M Wing includes a pair of S 102B Korpen (Raven) SIGINT aircraft that are based on the airframe of the Gulfstream IV business jet. Operated by a systems crew of four, the Korpen capability is based around a variant of TRW's Wideband Tactical Surveillance System (WTSS), which provides 20 MHz to 2 GHz band COMINT and up to 40 GHz ELINT coverage. Like many other applications of its kind, WTSS incorporates an air-to-ground datalink.

Intelligence collection
The UK Royal Air Force's (RAF's) No 51 Squadron is equipped with a trio of Nimrod R Mk 1 SIGINT aircraft that are capable of COMINT and ELINT functionality. Since coming into service in 1973, the Nimrod R Mk 1 has been the subject of two major upgrades and has been slated for a third.

In the first instance, the 1992 Starwindow effort is understood to have been aimed at the platform's COMINT subsystem and incorporated a network of 22 new digital receivers. The 1998 Project Extract addressed the modernisation of the aircraft's ELINT capabilities and was rebaselined during 2002 to incorporate new antennas and front-ends; some automatic functionality; a central database; and data fusion provision. Extract was completed during September 2003 and was to have been followed by Project Helix, which would have given the Nimrod an open architecture.

However, Helix appears to have withered on the vine as the RAF mulls whether to replace the aged Nimrod with a new platform. Possibilities include the lease of a number of US RC-135V/W 'Rivet Joint' (RJ) platforms.

The US itself fields a considerable airborne SIGINT capability, with dedicated platforms being operated by the US Air Force (USAF), US Navy (USN), US Army, the Air National Guard (ANG) and the Customs and Border Protection (CBP) agency.

The USAF capability is vested in two RC-135U 'Combat Sent' TECHINT, 17 RC-135V/W RJ COMINT/ELINT, three RC-135S Cobra BALL TELINT and 28 or so U-2S aircraft. Of these, the latest detailed RJ configuration is the Block 8, which is designed to provide an enhanced SIGINT collection capability, automated information dissemination, improved system reliability and enhanced user friendliness.

The Block 8 configuration can be recognised by its revised ventral antenna array and is expected to be joined by a Block 9 update in 2008-09. The RC-125U/V/W/S aircraft are operated by the USAF's 55th Wing. The RJ architecture also appears to form the basis of Saudi Arabia's pair of RE-3A/B SIGINT aircraft.

The ultra high-altitude U-2S' SIGINT capability takes the form of the Senior Glass COMINT/ELINT collection subsystem, a fully digitised variant of which was fielded during 2001. The U-2S has also acted as the testbed for Northrop Grumman's next-generation Airborne Signals Intelligence Payload (ASIP), five examples of which are expected to be used operationally by the U-2 fleet.

Looking to the future, theU-2S is scheduled to be replaced by the RQ-4 Global Hawk UAV starting in 2012. The RQ-4 Block 40 will carry an ASIP payload and Northrop Grumman is known to be undertaking work on ASIP applications for the US RC-12S 'Guardrail' SIGINT platform and the USAF's MQ-1 (ASIP-1C) and MQ-9 (ASIP-2C) UAVs. The U-2S is operated by the USAF's 9th Reconnaissance Wing.

The USN currently operates a fleet of 16 EP-3E COMINT/ELINT collection aircraft, the latest known update of which is designated as the Joint SIGINT Avionics Family (JSAF) Modernisation (JMOD) configuration. Launched in 2005, the JMOD was originally intended to be developed incrementally, with Spiral 1 introducing enhanced frequency coverage and Link 16 connectivity (amongst other things), Spiral 2 adding a data fusion/decision-making capability and Spiral 3 introducing a better low-band signal collection/direction-finding capability, remote tuning receivers and new antenna arrays (amongst others).

As currently planned, the EP-3E is set to be replaced by a new EP-X aircraft that was originally baselined to offer the same SIGINT capability as JMOD Spiral 3. Although billed as an EP-3E replacement, EP-X will be a multisensor platform that will incorporate SIGINT, radar and EO sensors. Aircraft in the service's current EP-3E fleet are assigned to USN squadrons VQ-1 and VQ-2.

Signals analysis
Within the US, the service is recapitalising 33 of its RC-12K/N/P/Q 'Guardrail' COMINT/ELINT aircraft to a common RC-12S standard that will introduce the Communication High Accuracy Location Subsystem-Compact (CHALS-C) geolocation system; an enhanced situational awareness (ESA) capability derived from the ASIP architecture; a new high-band COMINT capability; enhanced 'special signals' provision; and the X-MIDAS signals-processing package. Scheduled to enter service circa 2010, the RC-12S' COMINT subsystem also forms the basis of the COMINT system planned for the service's Aerial Common Sensor Increment 1 platform.

Within the ANG, the Utah-based 169th Intelligence Squadron is equipped with three roll-on/roll-off 'Senior Scout' COMINT/ELINT shelters that can be carried by 'quick-change' C-130 Super E, H, H1 and H2 transport aircraft. When carrying 'Senior Scout', such aircraft are fitted with clip-on antenna arrays (located on their main undercarriage and parachute doors, wingtips and tailcones) and as originally fielded 'Senior Scout' provided 2 kHz to 300 MHz band COMINT and 2-18 GHz band ELINT coverage. Elsewhere, the CBP is known to have operated a COMINT-configured P-3A aircraft registered as 'N16370', which is known to have been used in a counter-narcotics role.